Central tire inflation systems have been designed to adjust tire inflation so that tires will have better performance during different situations, such as during transport duty and during operation in the field. For example, to reduce undesirable compacting of the ground, systems for regulating tire pressure can reduce tire pressure during field operation in contrast to the higher pressure used during on-road operation. Certain vehicles, such as agricultural tractors, have rack and pinion “bar” type axles so that the wheels and tires can be placed at different positions on the axle. This allows the tread width of the vehicle to adapted to different situations. It is desired to provide an axle design which works with a tire inflation system on a vehicle which has an adjustable tread width. U.S. Pat. No. 6,435,238, issued in 200 shows a stationary axle with air conduits and ABS cables routed through the interior of the non-rotating axle. Other US patents, including U.S. Pat. No. 1,794,900, No. 4,387,931 No. 6,435,238 and No. 6,145,559 show designs where tire pressure passages pass through a vehicle axle. However, none of these design provide for both a supply pressure and a pilot pressure for a tire inflation control valve. And, none of these designs can accommodate a wheel and tire which can be placed at different positions on the axle.